The Cardinals are planning to select the contract of right-handed reliever Luis Gastelum, per reports from Jeff Jones of the Belleville News-Democrat and Derrick Goold of the St. Louis Post-Dispatch. The specific timing of the move is up in the air, perhaps pending how the pitching staff is used in today’s doubleheader. Jones notes that Gastelum was traveling to St. Louis this morning and would be on the roster within the next couple days.

Gastelum, 24, has enjoyed a terrific season in Triple-A thus far. He’s pitched 43 2/3 innings out of the bullpen and notched a 2.27 ERA with a 28% strikeout rate, 9.7% walk rate and 51% ground-ball rate. It’s an impressive season taken in total, but drilling down a bit, Gastelum has been even better than the surface-level numbers might indicate.

Nearly all of the damage against Gastelum this season has come in one awful outing. He’s allowed a total of 11 earned runs this season, but six of those came on May 13, when he faced nine batters from Miami’s Triple-A affiliate and recorded only two outs. Since that nightmare outing, Gastelum has been borderline unhittable. He allowed one run his next time out (four days later) … and hasn’t been scored on since. Gastelum has rattled off 22 1/3 shutout innings with a 30-to-5 K/BB ratio. He’s allowed only eight hits along the way.

Gastelum originally signed with the Cardinals as an amateur free agent out of Mexico three years ago. He’d never ranked among the Cardinals’ top 30 prospects coming into the season but had turned in consistent, quality numbers as he climbed the minor league ladder. This year’s dominant showing in Triple-A has jumped him to 21st and 25th among Cards minor leaguers on the midseason rankings at MLB.com and Baseball America. He’s not an especially hard-throwing reliever, sitting around 94 mph on his four-seamer and sinker, but scouting reports tout his changeup as a true plus pitch. He’s a pure bullpen prospect but one who has a chance to carve out a lasting role.